Case Study | Inconsistent Ankle Modulation

Assessment

Kira is a six-year-old child with a diagnosis of developmental delay. Her parents came to me seeking ongoing treatment for her gross motor development. She is experiencing difficulty maintaining an arousal level that supports social interaction, postural control or learning. However, an immediate concern was the position of her right foot in supported standing.

During the physical assessment, Kira displayed moderately low muscle tone in her trunk and extremities. Her musculoskeletal system assessment indicated she had full range of motion in all her joints. She displayed functional muscle strength in all her muscles; however, she had decreased endurance for all activities.

In sitting, I noted that Kira could maintain an upright position momentarily before collapsing into full spinal and hip flexion. With proprioceptive and vestibular sensory input, she was able to organize for activation of appropriate trunk musculature for midline postural control in sitting for very short periods of time. In supported standing, Kira’s trunk and lower extremities displayed atypical alignment. She hyperextended her lumbar spine, extended her hips and hyperextended her knees bilaterally. Her right foot was held in supination with weight bearing occurring at the lateral border of the foot (Fig.1).

Her motor system assessment revealed head and trunk righting reactions that were brief and inconsistent in prone, supine, sitting and standing. Protective extension was absent in her upper and lower extremities in all positions and planes of movement. Equilibrium reactions were absent, and there was no evidence of reactive or anticipatory postural adjustments. Kira’s alignment in supported standing was her attempt to organize postural control in a challenging position. However, this alignment put her lateral ligaments at risk and also provided her with minimal proprioceptive information.

Kira’s sensory system assessment revealed that she used her vision to make only brief eye contact with objects and people. She showed very low tolerance to touch at her mouth, hands and feet and displayed seeking of proprioceptive input by banging her feet and legs on the ground in both supine and sitting positions. Kira also sought vestibular input by extending her head (and sometimes her trunk) quickly back into extension followed by a quick return to the midline position.

Functionally, Kira maintained upright sitting on the floor or on a bench only momentarily before collapsing forward or pushing backward. She required full support in standing and bore minimal and inconsistent weight through her lower extremities. Kira did not initiate any transitional movement. It appeared that she was displaying a sensory based movement disorder.

I decided to begin treatment by providing Kira with increased proprioceptive and vestibular input in an organized manner resulting, I hope, in an appropriate arousal level. If so, treatment will shift to activation of muscles for strength and endurance during facilitation of postural control in sitting and standing. As Kira is able to maintain an appropriate arousal level for longer periods and her postural control improves, functional movement transitions and play will be introduced.

Bracing

Kira had no history of orthosis wear before this assessment. She displayed moderately low muscle tone throughout with no increased tone in any muscle groups and no range of motion limitation in her joints. There was no tendency to crouch gait and her knee hyperextension was mild. Finally, her varus forefoot position was correctable with minimal physical cueing to the lateral border of the foot.

Kira fits the Cascade Dafo description of a child who presents with inconsistent ankle modulation. She also weighs less than 40 pounds. Therefore, given her low tone, lack of joint limitation and low body weight, I chose a JumpStart orthosis rather than a DAFO 3.5 or DAFO 4. I used the Cascade foot sizing jig to measure her foot for an orthosis. I made a call to a Cascade Technical Support advisor before finalizing the order. He and I determined that, given the extent of Kira’s right-side supination, she would benefit from an instep strap. My advisor recommended a toe pad to discourage toe grasping. I ordered a JumpStart of the appropriate size by telephone along with the strap and toe pad.

Initial Fitting

During Kira’s initial fitting, I positioned and affixed the strap. I then positioned the toe pad with Kira in standing, leaving 1 cm. (.39 in.) of length beyond the end of her toes for growth. Finally, I trimmed the length of the JumpStart to the end of the toe pad using a pair of universal bandage scissors. In Figs. 2 and 3, Kira stands in her newly-fit JumpStart.

Thanks to her brace, Kira experienced immediate correction of the position of her right foot, and she began to unlock her knees periodically during this session. Kira also experienced activities in bench sitting and supported standing while wearing the JumpStart during the fitting session. The family and I developed a wearing schedule for home and school. Weekly physical therapy is ongoing.

Followup, Therapy and Wear

Kira’s ongoing weekly physical therapy sessions blend sensory processing strategies with Neuro-DevelopmentalTreatment. Kira is provided with organized proprioceptive and vestibular sensory input, which assists her in attaining and maintaining an appropriate arousal level for learning. Small, controlled weight shifts are facilitated in various positions to activate and strengthen Kira’s postural control musculature. Her JumpStart orthosis provides alignment at her right ankle for weight-bearing activities in bench sitting and standing that give her an appropriate base of support from which to move. We will gradually shape these weight shifts into controlled transitional movement with decreasing facilitation. Kira needs periodic sensory input throughout the session to maintain her arousal level so that she can learn how each movement feels and begin to access these movements during her activities of daily living.

Two months after Kira was fit, she is tolerating the JumpStart for 30 to 60 minutes in supported sitting (adapted chair) or in her stander. Her tolerance of the orthosis continues to be determined by her tactile defensiveness. The correction of the right foot alignment in sitting and standing with the JumpStart is excellent. The JumpStart has met the goal of correcting the alignment at the foot in order to preserve the integrity of the lateral ligaments and provide Kira with appropriate proprioceptive information.

With her foot in an appropriate alignment, Kira bears weight more consistently through her lower extremities in sitting and standing activities. Her joint integrity at the foot is no longer compromised. She is also bearing increased weight during sit-to-stand transfers and during supported standing. This assists greatly in her daily living activities. Her educational assistants report that they can now stand with Kira in supported standing rather than placing her in her stander during the morning announcements at school. Kira has recently begun to display carryover of neutral foot alignment when not wearing the JumpStart 80 percent of the time in supported standing. This carryover is not uncommon in children with a sensory based, rather than a neuro-motor, movement disorder.

When wearing the JumpStart during supported ambulation, Kira initially reverted back to decreased weight bearing on the right foot (drawing the leg up into hip/knee flexion), since the orthosis interfered with the pattern she used for postural control. In my practice, I have observed that it is not unusual for children with motor dysfunction to display disorganization of motor skills they have most recently acquired when they are fitted with a new orthosis that impacts their postural control. However, therapy continues to address activation of hip flexion with knee extension during assisted ambulation while wearing the JumpStart.

Kira has made good progress in her motor skills, and the JumpStart orthosis has provided a cost-effective, efficient means of maintaining appropriate right foot alignment.

— Shelley Mannell

Shelley Mannell, BSc., BHScPT, RegPT, is the founder of HeartSpace Physical Therapy for Children in St. Catharines, Ontario. She has been treating children with physical challenges and gross motor delays for 20 years. She is a registered physiotherapist with the College of Physiotherapy in Ontario and a member of the Canadian Physiotherapy Association and the Neuro-Developmental Treatment Association. In addition to her clinical work, Shelley served as a clinical faculty member at McMaster University for 10 years and teaches courses for therapists across Canada.

Fig. 1. Kira’s foot position, presenting pronounced supination, before treatment. Fig. 2. Posterior view of Kira’s improved foot position. Fig. 3. Kira’s anterior alignment. Although there is still some very mild supination, foot position is much improved. As Kira’s sensory defensiveness decreases, we expect to see more gains in approaching a neutral foot position.

Special Considerations

Sometimes, a facet of a patient’s world that may have nothing to do with gait becomes a primary concern in bracing. Kira’s situation is an illustration of this. She is a unique patient. She has full range of motion and can successfully integrate neuro-muscular movement. However, the low level of proprioceptive feedback she routinely processes combines with her high sensory defensiveness to make it difficult for Kira to interact physically with the world around her and even to wear a brace for very long. For this reason, helping her access appropriate levels of sensory input has been paramount in our goals for her treatment.

We use the JumpStart to improve her foot position, which helps Kira gain experience with appropriate sensory feedback through her foot. She is able to carry this experience over to other activities and is continuing to make progress even when not wearing the brace.